1. Field of the Invention
The present invention relates to an information processing terminal capable of noncontact wireless communication and a program for use with the terminal.
2. Description of the Related Art
Recent years have seen growing acceptance of IC tags and IC cards capable of noncontact wireless communication and information processing terminals such as mobile phones equipped with such an IC card each. The IC tag is typically embedded in the price tag of a product to indicate its price when scanned electronically. The IC card is illustratively arranged to store electronic money information for use in making payments. In a new development, IC card capabilities have been put into an IC card chip that is added to information processing terminal equipment. In this case, the balance of the electronic money in the IC card can be checked by way of the information processing terminal.
The information processing terminal in related art provided with the IC card function has a dual data processing arrangement: a terminal control unit (external CPU) for performing arithmetic operation specific to the terminal, and an IC card control unit for carrying out operations unique to the IC card capability. The two data processing sections execute their own applications without interfering with each other's data domain. If the IC card control unit may not keep up with its operations, part or all of the operations may be delegated to the terminal control unit for execution (e.g., see Japanese Patent Laid-open No. 2006-053874).
Still, it is preferred that the IC card control unit operate independently of the terminal control unit in order to maintain the reliability of the IC card. In view of possible functional expansion in the future, the IC card control unit built as an independent circuit typically has to adopt a high-performance CPU and a large-capacity memory.
As a result, even upon execution of such simple applications as data exchanges with a reader/writer (e.g., for checks on internal data of the card), it is necessary typical to start up and operate the high-performance IC card control unit. It has been difficult to reduce the amount of power consumed when the ponderous IC card function is activated. Although there have been proposed techniques for preparing a plurality of power supplies with different voltages aimed at lowering wasteful power consumption (e.g., see Japanese Patent Laid-open No. 2002-150250 and Japanese Patent No. 3617509), effective methods have yet to be disclosed for drastic reductions in power consumption of the IC card function.